UNIVERSITY   OF    CALIFORNIA 

COLLEGE    OF    AGRICULTURE 

AGRICULTURAL    EXPERIMENT   STATION 

BERKELEY,    CALIFORNIA 


STATIONARY  SPRAY  PLANTS 
IN  CALIFORNIA 

(A  Progress  Report) 
B.  D.  MOSES  and  W.  P.  DURUZ 

In  co-operation  with  T.  A.  WOOD,  of  the  California  Committee 
on  the  Relation  of  Electricity  to  Agriculture 


BULLETIN  406 

October,  1926 


UNIVERSITY  OF  CALIFORNIA  PRINTING  OFFICE 

BERKELEY,  CALIFORNIA 

1926 


FOREWORD 

This  bulletin  is  a  contribution  of  the  Divisions  of  Agricultural 
Engineering  and  Pomology  and  the  Stationary  Spraying  Sub-Com- 
mittee of  the  California  Committee  on  the  Relation  of  Electricity  to 
Agriculture.  It  is  the  first  of  a  series  planned  to  report  the  results 
of  investigations  conducted  jointly  by  the  Agricultural  Experiment 
Station,  College  of  Agriculture,  University  of  California,  and  the 
California  Committee  on  the  Relation  of  Electricity  to  Agriculture. 
This  committee  represents  the  agricultural  and  electrical  industries 
in  California  that  are  working  together  for  the  purpose  of  making 
available  reliable  information  concerning  the  use  of  electricity  on  the 
farm,  and  cooperating  with  similar  committees  in  other  states.* 

E.  D.  Merrill, 

Director,  California  Agricultural 
Experiment  Station. 


The  personnel  of  this  committee  for  1925-26  is : 
L.  J.  Fletcher,  College  of  Agriculture,  Chairman. 
N.  E.  Sutherland,  Pacific  Gas  and  Electric  Company,  Treasurer. 
B.  D.  Moses,  College  of  Agriculture,  Executive  Secretary. 
E.  H.  Alvord,  General  Electric  Company. 
H.  M.  Crawford,  Pacific  Gas  and  Electric  Company. 
J.  J.  Deuel,  California  Farm  Bureau  Federation. 

A.  M.  Frost,  San  Joaquin  Light  and  Power  Corporation. 
Alex.  Johnson,  California  Farm  Bureau  Federation. 

B.  M.  Maddox,  Southern  California  Edison  Company. 

C.  A.  Utley,  Pelton  Water  Wheel  Company. 


STATIONARY  SPRAY  PLANTS  IN 
CALIFORNIA1 

B.  D.  M0SES2  and  W.  P.  DUEUZ,3  m  cooperation 
with  T.  A.  WOOD* 


A  stationary  spray  plant,  as  the  name  would  imply,  is  an  outfit 
that  remains  in  a  fixed  place.  The  plant  consists  essentially  of  a 
power  unit  and  pump  of  sufficient  capacity  to  force  spray  liquids 
through  underground  pipes  to  all  parts  of  the  orchard.  At  convenient 
points  lengths  of  hose  are  attached  to  the  pipes  and  the  spray  material 
is  applied  to  the  trees  in  the  usual  way  through  spray  rods  or  spray 
guns. 

The  prevailing  method  of  spraying  orchards  has  been,  and  still  is, 
by  means  of  movable  sprayers.  The  common  type  consists  of  a  tank, 
gasoline  engine  and  pump  mounted  on  wheels  and  drawn  through 
the  orchard  by  a  team  or  tractor.  A  smaller  outfit  operated  by  man 
power  may  be  hauled  on  a  sled  or  wagon,  and  a  still  smaller  unit  may 
be  operated  by  hand  while  the  operator  carries  the  load  on  his  back. 

Nowhere,  perhaps,  has  the  combating  of  diseases  and  insects  affect- 
ing fruit  trees  been  a  more  serious  problem  than  in  California,  where 
the  mild  climate  favors  the  overwintering  of  many  pests.  The 
wholesale  planting  of  orchards  during  the  last  two  decades,  in  many 
instances  by  persons  unfamiliar  with  known  cultural  practices,  has 
tended  to  aggravate  the  situation.  New  insects  and  new  diseases  have 
been  introduced  from  other  states  and  countries.  Methods  of  com- 
bating pests  in  one  locality  or  district  have  been  found  inapplicable 
to  other  districts  with  different  climatic  conditions. 

The  earlier  deciduous  orchards  were  planted  along  the  coast  and 
in  coastal  valleys.  Later  plantings  followed  the  rivers  farther  inland. 
As  an  industry,  fruit  growing  soon  spread  into  the  interior  valleys 
and    the  adjacent    foothills    or    wherever    water    was    available    for 


i  The  writers  are  indebted  to  the  following  fruit  growers  who  have  generously 
cooperated  and  permitted  the  study  and  testing  of  their  stationary  spray  plants: 
Alfred  G.  Brown,  Santa  Clara;  E.  A.  Gammon,  Hood;  L.  B.  Landsborough,  with 
the  A.  B.  Humphrey  Kanch,  Mayhews;  W.  W.  Monroe,  Sebastopol;  Hayward 
Eeed,  Broderick;  Howard  Reed,  Marysville,  and  Adrian  C.  Wilcox,  Santa  Clara. 

2  Division  of  Agricultural   Engineering. 

3  Division  of  Pomology. 

4  California  Committee  on  the  Relation  of  Electricity  to  Agriculture. 


4  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION 

irrigation.  Soon  many  new  problems  in  spraying  had  to  be  met  and 
all  existing  knowledge  of  older  districts  in  the  eastern  states  and  even 
in  European  countries  was  drawn  upon,  but  in  the  end  our  experi- 
menters had  to  work  out  their  own  spraying  programs,  often  embrac- 
ing new  methods,  new  equipment,  and  even  new  materials. 

The  development  of  spraying  equipment  has  gone  forward  slowly 
and  conservatively.  Eastern  manufacturers,  in  the  main,  have  kept 
step  with  the  western  manufacturers  of  spraying  equipment,  par- 
ticularly as  regards  the  portable  gasoline  power  outfits.  However,  it 
remained  for  the  western  coast  to  devise  and  put  into  operation  a  new 
idea  in  spraying,  namely,  the  stationary  spray  plant.  Users  of 
portable  sprayers  have  often  had  some  difficulty  in  spraying  at 
exactly  the  proper  time  on  account  of  muddy  ground  in  the  orchard. 
The  ordinary  portable  spraying  outfit,  loaded  with  200  gallons  of 
liquid,  weighs  at  least  a  ton.  Obviously,  such  a  load  cannot  be  easily 
transported  through  an  orchard  just  after  a  heavy  rain  or  after  a 
thaw. 

A  still  greater  difficulty  in  spraying  arose  in  certain  California 
orchards  in  the  lowlands  adjacent  to  the  Sacramento  River,  which  at 
certain  times  in  the  winter  and  early  spring  were  apt  to  be  inundated. 
Prune  and  pear  orchards  along  the  river  were  sometimes  submerged 
to  a  depth  of  several  feet  for  a  week  at  a  time.  Owing  to  the  sandy 
nature  of  the  subsoil,  no  damage  resulted  to  the  trees  themselves  from 
the  submergence,  but  while  the  water  was  on  the  ground  and  for  several 
days  afterward,  it  was  impossible  to  spray.  Unfortunately,  one  of 
the  most  vital  spray  applications  for  pears  was  necessary  at  a  time 
when  it  was  utterly  impossible  to  enter  the  orchard  with  any  sort  of 
movable  outfit.  One  orchard  owner,  Mr.  Hayward  Reed,5  tried  the 
plan  of  mounting  a  sprayer  on  a  barge.  He  later  used  very  long 
lengths  of  hose  and  even  pipe-lines  in  order  to  spray  considerable 


5  "The  year  1906  was  a  disastrous  one  for  me,"  writes  Mr.  Keed.  "The  scab 
infection  was  so  bad  that  98  per  cent  of  the  crop  were  No.  2  and  No.  3  pears. 
Improper  spraying  was  the  cause.  The  following  year,  1907,  was  my  most  success- 
ful season.  High  grade  pears  with  other  favorable  conditions  made  this  possible. 
As  the  time  neared  for  scab  spraying,  a  great  flood  came  (fig.  1).  I  sprayed  in 
boats  while  I  could,  but  when  the  water  receded  some,  this  could  not  be  done. 
Wagons  also  were  of  no  avail.  In  a  quandary  I  told  Honda  (my  foreman)  to 
couple  the  hose  lengths  together  and  spray  as  far  as  possible.  We  kept  on  until 
a  thousand  feet  were  used.  At  that  time  I  conceived  the  idea  of  using  pipes. 
Knowing  how  much  cheaper  and  stronger  they  were,  I  felt  they  could  carry  the 
spray  material  long  distances,  and  that  hose  attached  at  different  intervals  would 
operate  successfully.  The  following  year,  1908,  I  installed  the  underground  pipe 
system  at  Rose  Orchard,  using  %-inch  pipe  for  main  and  laterals.  Since  then  I 
have  enlarged  the  system,  using  1^-inch  for  main  and  %-inch  for  laterals.  The 
year  1909  proved  the  value  of  the  pipe  system.  Another  great  flood  came.  Our 
spraying  was  done  on  time  by  men  working  in  gum  boots.  Later  I  installed  the 
system  in  the  New  England,  Folsom,  and  Gridley  orchards." 


Bul.  406] 


STATIONARY    SPRAY    PLANTS    IN    CALIFORNIA 


areas  from  high  ground.  This  finally  gave  him  the  idea  of  establish- 
ing a  central  pumping  plant  and  carrying  pipes  underground  from 
it  to  all  parts  of  the  orchard.  At  intervals  there  were  risers  located 
close  to  the  trees  so  they  would  be  out  of  the  way,  where  spray  hoses 
could  be  attached.     After  much  experimenting,  the  number  of  trees 


Fig.  1. — Flood  scenes  in  1906  in  the  Hayward  Eeed  orchard. 


possible  to  be  sprayed  economically  from  one  point  was  found.  Many 
other  details,  such  as  size  of  pipes  for  mains  and  laterals,  and  the 
required  capacity  of  the  pump  were  worked  out. 

Mr.  Reed's  system  proved  so  satisfactory  that  other  fruit  growers 
have  installed  similar  plants.    A  survey  made  in  1925  revealed  at  least 


6 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


ten  stationary  plants  in  successful  operation  in  California.  The  state 
of  Washington6  has  several  hundred  plants.  Most  of  these  are  located 
in  the  Wenatchee  and  Yakima  districts.  In  that  state  conditions 
making  it  difficult  to  spray  at  the  right  times  by  old  methods  have 
brought  about  this  extensive  use  of  the  stationary  outfits. 


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Fig.  2. — Diagram  of  stationary  spraying  system. 


s  Morris,  O.  M.,   Stationary  spray  plants,  Wash.  Agr.  Exp.  Sta.  Popular  Bui. 
125:1-20.     1924. 


Bul.  406] 


STATIONARY    SPRAY   PLANTS    IN    CALIFORNIA 


GENERAL   DESCRIPTION 

Figure  2  shows  diagrammatically  the  general  arrangement  of  the 
underground  pipes  in  a  stationary  spray  system.  The  location  of  the 
pumping  station  is  governed  by  the  size  of  the  orchard,  water  supply, 
power  lines,  roads,  ranch  buildings,  and  the  topography  of  the  land. 
It  is  usually  near  the  center  of  the  orchard.  The  equipment  of  the 
pumping  station  consists  of  a  heavy  duty  spray  pump  driven  by  an 


Fig.  3. — Pumping  station  of  the  two- story  type.  The  lower  floor  is  used  for 
the  service  tank,  pump,  and  motor,  while  the  upper  floor  is  for  mixing  the 
materials.  The  auxiliary  water  tank  is  a  recommended  accessory  in  order  to 
insure  plenty  of  water  when  needed. 

electric  motor  or  a  gas  engine  and  provided  with  mixing  and  service 
tanks.  The  equipment  used  on  portable  rigs  may  be  employed  in  the 
stationary  plant,  but  provision  must  be  made  for  any  increase  in 
pressure  or  discharge. 

A  main  line  is  laid  from  the  pump  through  the  center  or  along 
one  side  of  the  orchard  with  laterals  leading  off  from  it.  Outlets  are 
systematically  provided  on  laterals  so  that  hose  may  be  attached  for 
spraying  the  trees.  All  permanent  piping  is  laid  about  eighteen  inches 
below  the  surface  of  the  ground  so  as  not  to  interfere  with  tillage. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 


DESCRIPTION   OF  SEPARATE    UNITS 

Housing. — The  pumping  equipment  should  be  housed  in  a  suitable 
building,  the  type  depending  upon  whether  it  is  to  be  used  solely  for 
housing  spray  machinery  and  materials  or  for  other  purposes  as  well. 
Figure  3  shows  a  type  of  building  which  is  used  for  spraying  only; 
figure  4,  the  interior  of  a  building  used  for  spraying,  for  storage,  and 
for  housing  an  irrigation  pump,  and  figure  5,  a  building  which  is  used 
as  a  farm  shop  as  well  as  for  storage.  The  main  essential  is  to  have  the 
building  so  arranged  as  to  facilitate  the  handling  of  spray  materials. 

Power  Unit. — The  power  unit  consists  of  either  an  electric  motor 
or  a  gas  engine  and  the  power  is  transmitted  to  the  pump  by  belt, 
gears,  or  chain  (fig.  6).  Any  standard  electric  motor  may  be  used, 
ranging  from  5  to  15  horsepower,  according  to  the  size  of  the  pump 
and  the  pressure  to  be  maintained.  If  a  belt  drive  is  used,  the  motor 
should  be  connected  to  the  pump  with  a  belt  of  correct  length  to 
prevent  "belt  slap,"  using  pulleys  of  proper  sizes  to  obtain  the  speed 
specified  for  the  pump. 

For  an  electric  installation,  the  line  from  the  transformer  to  the 
motor  should  not  be  excessively  long  and  wire  of  the  proper  size  should 
be  used  to  avoid  excessive  voltage  drop.  The  motor  base,  starter  box, 
and  switch  box  should,  of  course,  be  grounded.  This  precaution  is 
especially  important  since  the  floor  of  the  pump  house  is  usually  wet. 

If  a  gas  engine  is  used,  it  should  be  equipped  with  a  reliable 
governor  in  order  to  avoid  damage  from  excessive  engine  speeds. 

Pump. — A  heavy  duty  pump  is  necessary  to  develop  high  pressures 
at  the  nozzles.  In  long  lines  of  pipe,  where  several  nozzles  are  used 
and  velocities  through  the  pipe  are  relatively  high,  pump  pressures 
as  great  as  400  pounds  to  the  square  inch  are  necessary.  In  short  lines 
of  pipe,  pump  pressures  vary  from  250  to  300  pounds  to  the  square 
inch.  Because  of  the  heavy  duty  performed  by  it,  the  pump  must  be 
placed  on  a  solid  base,  preferably  concrete. 

Tanks. — Two  round-bottomed  wooden  tanks,  similar  to  those  on 
portable  rigs,  are  commonly  used,  both  for  mixing  the  liquid  and  serv- 
ing the  pump.  Such  tanks  range  in  size  from  200  to  1000  gallons  each. 
Two  systems  of  arrangement  are  followed :  in  one,  a  small  mixing  tank 
is  on  a  higher  level  than  the  larger  service  tank,  and  in  the  other,  both 
tanks  are  of  the  same  size  and  on  the  same  level.  In  the  first  arrange- 
ment the  service  tank  is  replenished  from  the  mixing  tank  (figs.  3 
and  4),  while  in  the  second  the  tanks  are  alternately  used  for  mixing 
and  service  by  transferring  the  suction  hose  or  by  operating  a  two-way 
valve  on  the  pump  suction  (fig.  7). 


Bul.  406] 


STATIONARY    SPRAY    PLANTS    IN    CALIFORNIA 


9 


Each  tank  is  fitted  with  its  own  agitator  driven  from  the  pump 
shaft.  In  some  instances  the  agitator  of  the  mixing  tank  is  horizontal 
and  is  driven  from  the  tail-end  of  the  agitator  shaft  of  the  service 
tank.    In  other  cases  the  agitator  is  vertical  and  is  driven  by  a  shaft 


Fig.  4. — Interior  of  pumping  station. 
a.  Shows  service  tank  with  vertical  agitator. 

T).  Shows  mixing  tank,  service  tank,  and  pump.    Belts  connect  with  a 
35-h.p.  electric  motor  which  is  also  used  for  pumping  water  for  irrigation. 


10 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 


Fig.  5. — A  well-planned  pumping  station  which  has  many  conveniences.  The 
mixing  of  spray  materials  is  facilitated  by  a  vat  in  the  ground,  into  which  the 
lime-sulfur  is  poured  from  the  barrels  and  then  pumped  by  means  of  a  hand 
pump  to  the  mixing  tank.  The  brick  furnace  is  used  in  heating  water  for  oil 
emulsions.  The  far  end  of  this  building  is  used  as  a  farm  shop  and  for  storage. 
The  photograph  shows  an  auxiliary  portable  sprayer  being  filled  from  the  same 
mixing  tank  that  is  used  for  the  stationary  system. 


Fig.  6. — A  typical  installation  showing  mixing  tank,  pump,  and  power 
unit.     A  10-hp.  electric  motor  is  used  for  driving  the  pump. 


BUL.  406]  STATIONARY    SPRAY   PLANTS   IN    CALIFORNIA  11 

and  gears  from  the  power  unit.  Vertical  agitators  in  flat-bottomed 
tanks  (fig.  4)  require  special  attention  because  of  the  tendency  of  the 
mixture,  as  a  whole,  to  whirl,  causing  heavy  materials  in  suspension 
to  settle  along  the  sides  and  bottom.  This  objection  is  not  found  with 
horizontal  agitators  in  the  round-bottomed  tanks. 

An  adequate  supply  of  water  should  be  piped  to  the  tanks,  either 
from  a  reservoir,  tank,  or  pump,  as  shown  in  figures  3  and  5. 

Pipe  Lines. — After  a  careful  study  of  the  orchard  topography  and 
tree  spacing,  a  piping  diagram  should  be  drawn  and  the  trenches  dug 
accordingly  (fig.  8).    Galvanized  iron  pipe  with  screw  fittings  should 


Fig.  7. — This  illustrates  two  tanks  on  the  same  level.     Each  in  turn 
serves  as  a  mixing  tank  and  a  service  tank. 

be  selected  to  stand  the  pressure  under  which  it  is  to  operate  (see 
table  1).  The  pipe  lines  consist  of  mains,  1  to  1%  inches  in  diameter, 
and  laterals  %  to  1  inch  in  diameter,  with  gate  valves  between  the 
pump  and  the  mains  and  at  the  head  of  each  lateral  (fig.  9).  This 
arrangement  facilitates  flushing  the  line  and  also  aids  in  preventing 
the  settling  of  spray  material  in  laterals  not  being  used.  Frequent  use 
of  unions  is  recommended  so  as  to  simplif}^  future  repairs  or  altera- 
tions in  the  line.  Because  of  the  high  pressures  to  be  maintained,  good 
pipe-compound  must  be  used  in  making  connections,  and  the  pipe  and 
fittings  must  be  screwed  tight.  Abrupt  turns  in  the  line  should  be 
avoided  wherever  possible.  Long  radius  bends  are  better  than  ordinary 
short  elbows.  All  pipe  should  be  carefully  reamed  so  as  to  eliminate 
constrictions  from  cutting  or  threading.  These  precautions  will  reduce 
friction  losses  and  permit  high  nozzle  pressures.  Table  2  gives  the 
friction  loss  per  thousand  feet  for  ordinary  and  for  old  iron  pipe. 


r  f 


tt  ft 


6 
Fig.  8. 

a.  Connecting  pipe  before  lowering  into  the  trench. 

b.  Laying  the  pipe  to  an  even  grade  by  means  of  a  level  before  covering. 


Bul.  406] 


STATIONARY    SPRAY   PLANTS   IN    CALIFORNIA 


13 


It  is  a  customary  practice  to  place  a  lateral  at  every  eighth  row  of 
trees  and  a  riser  or  service  connection  at  every  fifth  tree  in  the  row. 
This  may  be  modified  for  different  orchards,  according  to  the  planting 
distance,  but  in  any  case  the  risers  should  be  not  more  than  150  or 
160  feet  apart  to  avoid  hose  lengths  of  more  than  100  feet. 

Figure  10  shows  the  location  of  risers  in  different  orchards.  If 
they  are  permanent,  the  risers  should  be  protected  by  posts  or  should 
be  located  near  trees;  temporary  risers  should  be  removed  after  each 
spraying  period,  the  fittings  for  the  connection  being  located  at  the 


Fig.  9. — Gate  valves  on  the  main  and  lateral  should  be  provided. 


TABLE  1 

Strength  of  New  Butt-welded  Wrought  Steel  Pipe  in  Pounds  per 

Square  Inch* 


Standard 

Extra  strong 

Double  extra  strong 

Size, 
inches 

Bursting 
pressure, 
Barlow's 
formula 

Working 
pressure 

Bursting 
pressure, 
Barlow's 
formula 

Working 
pressure 

Bursting 
pressure, 
Barlow's 
formula 

Working 
pressure 

lA 

10,384 

1298 

14,000 

1750 

28,000 

3,500 

% 

8,608 

1076 

11,728 

1716 

23,464 

2,933 

l 

8,088 

1011 

10,888 

1611 

21,776 

2,722 

Vi 

6,744 

843 

9,200 

1150 

18,408 

2,301 

VA 

6,104 

763 

8,416 

1052 

16,840 

2,105 

2 

5,184 

648 

7,336 

917 

14,680 

1,835 

VA 

5,648 

706 

7,680 

960 

15,360 

1,920 

3 

4,936 

617 

6,856 

857 

13,714 

1,714 

*  Note. — After  Crane  Company  Catalogue  50  :  626.  1917.  The  safe  working  pressure  varies  from 
617  pounds  per  square  inch  in  the  three-inch  pipe  to  1298  pounds  per  square  inch  in  the  J^-inch  pipe,  all 
of  which  are  higher  than  the  pressures  likely  to  be  obtained  at  any  time  in  the  piping  systems.  Since 
standard  fittings  and  valves  do  not  carry  quite  as  high  pressures  as  the  standard  pipe,  it  may  be  better 
to  use  heavy  valves,  especially  in  the  larger  sizes. 


14 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


intersection  of  diagonals  between  trees.     Each  riser  is  fitted  with  a 
service  cock  and  a  hose  coupling. 

Hose. — The  best  quality  high  pressure  rubber  hose  must  be  used 
in  order  to  withstand  the  heavy  pressure  and  hard  service  to  which 
it  is  subjected  when  dragged  through  the  orchard.  The  size  is  usually 
%6-inch  and  the  length  should  not  be  over  100  feet  (fig.  11). 


3  -A^  **•  •■■  -"*.* 


Fig.  10. — Four  types  of  risers. 

a.  Double  gate  valve.  c.  Garden  valve. 

fc.  Service  cock.  d.  Gate  valve. 


Fig.  11. — Spraying  by  means  of  the  stationary  system. 

a.  Using  spray  rod  with  200  feet  of  hose.  A  helper  is  necessary  to  assist  in 
moving  the  hose  about. 

T).  Using  the  spray  gun  with  74  feet  of  hose.  One  man  can  handle  this 
length  satisfactorily. 


16 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 


TABLE  2 
Friction  Drop  in  Pipes  for  Various  Bates  of  Discharge* 


}4  in.  Wrought  iron  pipe, 
actual  inside  diameter  .623  in. 

%  in.  Wrought  iron  pipe, 
actual  inside  diameter  .824  in. 

1  in.  Wrought  iron  pipe, 
actual  inside  diameter  1.048  in. 

Dis- 
charge 
gal. 

Velocity 

in  ft. 
per  sec. 

Pressure  drop  per 
1000  ft.  of  pipe  in  lbs. 

Velocity 

in  ft. 
per  sec. 

Pressure  drop  per 
1000  ft.  of  pipe  in  lbs. 

Velocity 

in  ft. 
per  sec. 

Pressure  drop  per 
1000  ft.  of  pipe  in  lbs. 

per 
min. 

Ordinary 
iron 

Old 
iron 

Ordinary 
iron 

Old 
iron 

Ordinary 
iron 

Old 
iron 

1 

1.05 
2.10 
3.16 
4.21 
5.26 
6.31 
7.37 
8.42 
9.47 
10.52 

9.1 
32.2 
68.5 
117.3 
177.8 
247.2 
329.5 
425.0 
525.0 
637.5 

13.45 
48.6 
104.2 
177.8 
268.8 
377.3 
498.5 
642. 
793.5 
967.0 

2 

1.20 
1.80 
2.41 
3.01 
3.61 

8.24 
17.78 
30.35 
46.05 
63.7 

12.58 

26.45 

46.05 

68.9 

97.1 

3 
4 
5 
6 

7 

1.12 
1.49 
1.86 
2.23 

5.47 

9.28 

14.09 

19.73 

8.24 
14.01 
21.29 
29.92 

8 
9 

4.81 

108.4 

164.8 

2.98 

33.82 

50.7 

10 
12 

6.02 

7.22 

164.8 
229.8 

253.0 
343.5 

3.72 
4.46 
5.20 

50.7 
71.1 
95.4 

76.8 
108.4 

14 

143.2 

15 

9.02 

343.5 

529.0 

16 

5.95 
6.69 
7.44 

121.4 
151.8 
182.2 

182.2 

18 

225.5 

20 

12.03 

589.5 

893.0 

277.5 

22 

24 

25 

9.30 

277.5 

416.3 

26 

28 

30 

11.15 
13.02 

14.88 

385.8 

516. 

659. 

585. 

35 

781. 

40 

998. 

45 

50 

*  Adapted  from  Williams  and  Hazen,  Hydraulic  Tables,  3rd  edition,  pp.  26-29, 1920.    Publisher- 
John  Wiley  &  Sons,  Inc.,  New  York. 


Bitl.  406] 


STATIONARY    SPRAY    PLANTS    IN    CALIFORNIA 


17 


TABLE  2— (Concluded) 
Friction"  Drop  in  Pipes  for  Various  Bates  of  Discharge* 


\\i  in.  Wrought  iron  pipe, 
actual  inside  diameter  1.380  in. 

\XA.  in.  Wrought  iron  pipe, 
actual  inside  diameter  1.611  in. 

2  in.  Pipe  or  hose,  actual 
inside  diameter  2.00  in. 

Dis- 
charge 
gal. 
per 

Velocity 

in  ft. 
per  sec. 

Pressure  drop  per 

1000  ft.  of  pipe 

in  lbs. 

Velocity 

in  ft. 
per  sec. 

Pressure  drop  per 

1000  ft.  of  pipe 

in  lbs. 

Velocity 
in  ft. 
per  sec. 

Pressure  drop  per 

1000  ft.  of  pipe  or 

hose  in  lbs. 

min. 

Ordinary 
iron 

Old 
iron 

Ordinary 
iron 

Old 
iron 

Ordinary 

Old 

1 

2 

3 

4 

.86 
1.07 
1.29 
1.50 
1.72 

2.47 
3.64 
5.20 
6.90 

8.81 

3.73 

5.51 

7.89 

10.41 

13.45 

.63 
.79 
.94 
1.10 
1.26 
1.42 
1.57 
1.89 
2.20 

1.137 
1.726 

2.428 
3.208 
4.12 
5.12 
6.20 
8.72 
11.62 

1.735 
2.602 
3.642 
4.355 
6.20 
7.76 
9.41 
13.18 
17.56 

5 

6 

7 

.61 

.868 

1.258 

8 
9 

.82 

1.432 

2.168 

10 
12 
14 
15 

2.14 
2.57 
3.00 

13.23 
18.65 
24.72 

19.95 

28.2 
37.7 

1.02 
1.23 
1.43 

2.168 
3.035 
4.075 

3.295 

4.64 

6.16 

16 
18 
20 
22 

3.43 

3.86 
4.29 

31.65 
39.45 

48.3 

48.3 
59.4 
72.9 

2.52 

2.83 
3.15 
3.46 

3.78 

14.78 
18.39 
22.55 
26.88 
31.65 

22.54 

27.74 
33.82 
40.32 
46.82 

1.63 
1.84 
2.04 

5.204 
6.46 

7.89 

7.89 

9.84 

11.93 

24 

25 

5.36 

72.0 

108.8 

2.55 

11.84 

18.04 

26 

4.09 
4.41 
4.72 
5.51 
6.30 
7.08 
7.87 

36.42 
42.06 
47.68 
63.75 
81.5 
100.6 
123.2 

55.07 
63.3 

71.98 

95.4 

121.8 

151.8 

185.6 

28 

30 
35 
40 
45 

6.43 
7.51 

8.58 

101.8 
135.3 
173.5 

155.2 
207.5 
264.5 

3.06 
3.57 
4.08 
4.60 
5.11 

16.65 
22.12 
28.62 
35.55 
42.92 

25.15 
33.82 
42.92 
53.3 

50 

10.72 

260.1 

398.8 

65.05 

*  Adapted  from  Williams  and  Hazen,  Hydraulic  Tables,  3rd  edition,  pp.  26-29,  1920. 
John  Wiley  &  Sons,  Inc.,  New  York. 


Publisher- 


18 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


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BUL.  406]  STATIONARY    SPRAY   PLANTS   IN    CALIFORNIA  19 


FIELD   OBSERVATIONS 

In  order  to  obtain  first-hand  knowledge  of  the  stationary  spray 
systems  as  they  are  operated  in  California,  the  writers  made  a  per- 
sonal canvas  of  the  state,  locating  six  such  installations  and  securing 
the  cooperation  of  the  owners.  Three  different  methods  for  securing 
information  were  used:  (1)  field  observations,  (2)  questionnaires  to 
owners,  and  (3)  field  tests. 

The  results  of  this  investigation  are  given  in  tabular  form.  Table 
3  gives  a  physical  description  of  the  six  orchards  upon  which  ten 
separate  tests  were  run.  Table  4  gives  the  conditions  under  which  the 
tests  were  run  and  the  results  obtained.  Tables  5  and  6  have  been 
compiled  from  the  information  furnished  by  the  owners  and  from 
data  secured  during  the  tests. 

Operation  of  the  System. — At  the  beginning  of  the  spraying 
period  the  pump  and  power  unit  are  inspected,  risers  installed,  if  they 
are  not  already  in  place,  and  hose  couplings  attached.  The  foreman 
directs  his  men  according  to  the  plan  of  spraying  to  be  followed. 
Helpers  become  necessary  when  long  lengths  of  hose  are  used.  Where 
risers  are  fitted  with  double  service  cocks,  one  helper  can  take  care 
of  two  or  more  hose  (fig.  10a).  It  is  a  good  plan  to  distribute  the 
hose  throughout  the  orchard,  using  different  laterals  and  thereby 
maintaining  satisfactory  nozzle  pressures. 

The  pump  is  started  and  all  lines  are  filled  with  water  to  prevent 
the  subsequent  filling  of  unused  pipes  with  spray  liquid.  All  valves 
are  then  closed  including  the  cut-off  cock  at  the  pump.  The  spray 
mixture  is  prepared  and  the  service  tank  filled  (fig.  12). 

Meanwhile  the  men  in  the  orchard  have  connected  their  hose  and 
opened  the  proper  service  cocks.  When  the  mixture  in  the  tank  has 
been  thoroughly  agitated  and  sufficient  pressure  developed,  the  cut-off 
cock  at  the  pump  is  opened,  thus  applying  pressure  to  the  piping 
system.    As  soon  as  the  clear  water  has  been  expelled,  spraying  begins. 

In  the  spraying  operation  each  man  with  a  hose  adopts  a  definite 
system  to  prevent  missing  trees  or  portions  of  trees  and  to  avoid 
winding  the  hose  around  trees  already  sprayed.  Figure  13  shows  a 
good  system  to  follow.  As  spraying  progresses,  new  laterals  are 
turned  on  and  the  old  ones  shut  off. 

At  the  end  of  the  day  that  part  of  the  system  which  has  been  used 
is  flushed  out  by  pumping  clear  water  through  this  part  of  the  pipe- 


20 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Fig.   12. 


-Showing  methods  by  which  concentrated  lime-sulfur  is  conveyed 
to  the  mixing  tank. 


a.  Dipping  the  concentrated  solution  from  an  underground  reservoir  and  carry- 
ing it  in  buckets  to  the  mixing  tank.  b.  Using  suction  pump  to  lift  solution  from 
an  underground  reservoir  to  the  mixing  tank.  c.  A  suction  hose  withdrawing  the 
liquid  directly  from  a  barrel  of  the  concentrated  solution,  d.  Lifting  a  full  barrel 
to  the  mixing  platform. 


Bul.  406] 


STATIONARY   SPRAY   PLANTS   IN    CALIFORNIA 


21 


line.  Flushing  is  accomplished  by  changing  the  suction  from  the 
service  tank  to  the  water  supply  by  means  of  cross  valves,  or  by  filling 
the  service  tank  itself  with  water.  Men  on  the  last  lateral  continue 
spraying  until  clear  water  appears.  The  foreman  determines  when 
to  turn  in  clear  water  in  order  to  finish  spraying  before  quitting 
time;  flushing  is  thus  completed  soon  after  spraying  is  finished. 
Thorough  flushing  is  especially  important  after  spraying  with 
materials  such  as  arsenate  of  lead  or  Bordeaux  mixture. 


Laterals - 


rf^-Q/ser 


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f     j       —   Pbth  taken  by  nozz/emon. 

— ^—- — — Path  taken  by  he/per  changing  t?ose 

from  one  riser  to  another. 


Fig.  13. — A  plan  for  routing  nozzle-man  so  that  no  trees  will  be  missed. 

The  diagram  is  simply  suggestive,  the  purpose  being  to  illustrate  how  the 
nozzle-man  can  be  routed  so  as  not  to  miss  any  trees,  and  so  as  to  prevent 
twisting  and  tangling  of  the  hose.  Three  blocks  are  shown,  the  detail  path 
for  the  last  three  trees  only  is  shown  in  the  upper  left-hand  block,  to  illustrate 
how  the  connection  may  be  transferred  from  one  riser  to  another.  The  first 
route  in  the  lower  right-hand  block  is  shown  in  detail,  to  illustrate  the  method 
of  transferring  from  one  riser  to  another  at  the  end  of  the  lateral. 


22 


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BUL.  406]  STATIONARY   SPRAY   PLANTS   IN    CALIFORNIA  23 


FIELD  TESTS 

The  object  of  the  tests  was  to  determine  the  mechanical  features 
and  characteristics  of  the  systems  in  use  and  to  cooperate  with  owners 
and  manufacturers  with  the  purpose  of  suggesting  improvements. 

Points  Investigated. — The  following  points  were  investigated : 

1.  Voltage  at  the  motor  and  line  drop. 

2.  Power  required. 

3.  Power  factor. 

4.  Speed  of  motor  and  pump. 

5.  Accuracy  of  pressure  gauges. 

6.  Pressure  drop  in  pipe  lines  and  hose. 

7.  Exact  pressure  at  nozzles. 

8.  Quantity  discharged  at  nozzles. 

9.  Uniformity  of  spray  liquid. 
10.  Time  required  for  spraying. 

Procedure. — Wattmeters,  voltmeters,  and  ammeters  were  connected 
into  the  circuit  ahead  of  the  starting  switch,  in  order  to  obtain  the 
electrical  characteristics  of  each  phase.  When  the  plant  was  in  regular 
operation,  readings  were  taken  of  voltage,  power,  current,  motor 
speed,  pump  speed,  and  pump  pressure.  The  pressure  gauges  were 
calibrated  by  comparison  with  a  test  gauge.  The  field  observations 
consisted  of  reading  the  pressures  at  risers  and  nozzles,  measuring  the 
quantity  of  discharge,  and  taking  samples  of  the  spray. 

Discussion  of  Results. — The  voltage  drop  is  dependent  upon  the 
distance  from  the  transformer  to  the  motor,  the  size  of  the  wire,  and 
the  power  demand  on  the  motor.  The  importance  of  short  lines  and 
large  wires  is  illustrated  by  the  two  following  cases :  With  a  7.5  horse- 
power motor,  2500  feet  from  the  transformer,  connected  by  No.  8  wire, 
on  a  220-volt  circuit,  there  was  found  to  be  a  drop  of  35  volts ;  while 
with  a  35-horsepower  motor,  50  feet  from  the  transformer,  and  con- 
nected with  No.  6  wire  on  a  220-volt  line  the  voltage  drop  was  only 
3  volts. 

There  was  a  rather  wide  range  of  power  consumed,  varying  from 
3.17  to  12.01  horsepower.  The  factors  governing  the  power  were  the 
pressure  maintained  at  the  pump,  the  size  and  speed  of  the  pump,  and 
the  efficiency  of  the  plant.  For  highest  efficiency,  the  motor  should 
carry  a  full  load  and  the  pump  should  have  a  capacity  little  more 
than  the  combined  requirement  of  the  nozzles. 


24  UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 

The  power  factor  at  the  motor  varies  with  the  size  of  the  motor, 
its  load,  and  the  power  factor  of  the  feeding  circuit.  This  was  found 
to  range  between  34  per  cent  for  a  15  horsepower  motor  with  one- 
quarter  load  and  81.5  per  cent  on  a  7.5  horsepower  motor  with  a  full 
load  (table  4).  It  is  evident,  therefore,  that  a  motor  should  be  chosen 
with  the  manufacturer's  rating  about  equal  to  its  load,  in  order  that 
the  power  factor  may  be  high.  The  efficiency  of  an  induction  motor 
running  with  a  low  power  factor  is  low,  and,  therefore,  is  expensive 
to  operate.  A  low  power  factor  places  an  unnecessary  burden  on  both 
the  consumer  and  the  power  company. 

The  pump  speeds  ranged  from  38  to  59  r.p.m.,  and  the  motor 
speeds  from  840  to  1203  r.p.m.  It  was  found  that  one  pump  was 
operating  15  r.p.m.  above  its  rated  speed  because  of  the  incorrect 
selection  of  pulleys. 

The  pressure  gauges  in  every  test  were  found  to  be  inaccurate,  in 
some  cases  the  error  was  as  high  as  50  pounds  to  the  square  inch. 
Water-logged  air  chambers  were  a  common  occurrence  and  were 
undoubtedly  responsible  for  damaged  gauges. 

The  friction  drop  depends  upon  the  size  and  length  of  the  main 
and  laterals  in  operation,  the  condition  of  the  inside  of  the  pipe, 
the  character  of  fittings  and  turns,  the  kind  of  liquid,  and  the  rate  of 
flow  (table  2).  A  small  pressure  drop  can  be  obtained  by  the  use  of 
large  pipe.  However,  if  too  large  pipe  is  used,  the  velocity  will  be  so 
low  as  to  permit  settling  out  of  heavy  chemicals  in  suspension,  a  con- 
dition which  may  result  in  uneven  concentrations  being  applied  to  the 
trees.  The  orchards  tested  showed  no  such  trouble  with  present  instal- 
lations. KSamples  of  spray  liquid  collected  from  the  nozzles  in  the  several 
orchards  showed  practically  the  same  concentrations  at  various  points. 
The  tests  showed  that  1  to  1%-inch  mains  and  %  to  1-inch  laterals 
give  the  best  practical  results.  In  one  orchard  which  had  a  1-inch 
main  1100  feet  long,  and  %-inch  lateral  200  feet  long,  the  pressure 
drop  from  pump  to  nozzle  was  115  pounds,  when  three  spray  guns 
were  in  operation.  This  excessive  loss  in  pressure  may  be  decreased 
by  two  methods:  first  by  increasing  the  size  of  the  main,  and  second 
by  decreasing  the  number  of  nozzles  per  lateral. 

In  order  to  determine  the  relation  between  pressure  drop  and  the 
number  of  nozzles  in  operation,  several  tests  were  run  at  two  orchards. 
A  pressure  gauge  was  inserted  directly  back  of  the  nozzle  and  read- 
ings were  taken  while  neighboring  nozzles  were  alternately  opened 
and  closed. 


Bui*.  406] 


STATIONARY    SPRAY   PLANTS    IN    CALIFORNIA 


25 


In  one  test  two  nozzles  were  operating  on  862  feet  of  lV^-inch  main 
and  1460  feet  of  %-inch  lateral.  Nozzles  on  other  laterals  were  in 
operation  while  the  following  readings  were  taken : 


Average  pump  pressure 

Nozzle  No.  1 

Nozzle  No.  2 

Pressure  at  No.  1 

Lbs.  per  sq.  in. 
200 
200 
200 

Open 

Closed 

Closed 

Open 
Open 
Closed 

Lbs.  per  sq.  in. 
140 
170 
180 

In  the  second  orchard,  the  pressure  readings  were  taken  with  three 
nozzles  in  operation.  The  main  was  960  feet  of  1-inch  pipe  and  the 
lateral  1080  feet  of  %-inch  pipe  to  riser  No.  1,  1160  feet  to  riser 
No.  2,  and  1240  feet  to  riser  No.  3.  The  following  readings  were 
taken : 


Pump 
pressure 

Nozzle 
No.  1 

Nozzle 
No.  2 

Nozzle 
No.  3 

Pressure  at 
No.  1 

Pressure  at 
No.  2 

Pressure  at 
No.  3 

Lbs. 

per  sq.  in. 

410-20 

410-20 

Open 

Closed 

Closed 

Open 
Open 
Closed 

Open 
Open 
Open 

Lbs. 
per  sq.  in. 

187 

Lbs. 
per  sq.  in.' 
172 
236 
337 

Lbs. 

per  sq.  in. 

165 

225 

410-20 

295 

In  this  same  test  pressure  gauges  were  inserted  between  the  service 
cock  and  the  hose.  These  results  are  only  indicative  because  the 
condition  of  the  hose  and  disks  is  constantly  changing.  The  following 
show  the  readings  of  the  gauges  with  115  feet  of  %6-incn  hose : 


Riser 

Pressure 

Pressure  drop  in  hose 

pressure 

Nozzle  No.  1 

Nozzle  No.  2 

Nozzle  No.  3 

No.  1 

No.  2 

No.  3 

Lbs. 

per  sq.  in. 

192 

Lbs. 
per  sq.  in. 

Lbs. 

per  sq.  in. 

172 

Lbs. 

per  sq.  in. 

165 

170 

Lbs. 

Lbs. 
20 

Lbs. 

27 

197 

27 

202 

187 
192 

15 
14 

206 

261 

236 

225 
295 

25 

36 

335 

40 

26 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 


Table  5  has  been  made  from  data  given  in  questionnaires  filled  out 
by  the  owners  and  from  data  in  previous  tables,  to  show  the  acreage 
covered,  number  of  trees  sprayed,  and  the  amount  of  spray  applied. 

TABLE  5 
Eesults  of  Computations  on  Kate  of  Spraying 


Test  group 


Total  gallons  of  spray 

Acres  sprayed 

Number  of  nozzles  in  opera- 
tion*  

Total  number  of  men  employed 

Total  number  of  trees 

Trees  to  the  acre 

Hours  to  spray 

Acres  sprayed  per  hour 

Trees  sprayed  per  hour 

Gallons  per  nozzle  per  hour 

Acres  sprayed  per  nozzle  per 
hour 

Trees  sprayed  per  nozzle  per 
hour 

Gallons  per  tree 


71,756 
260 

13r 

30 
20,200 
77.7 
61.5 
4.23 
328.5 
89.7 

.325 

25.3 
3.55 


23,200 
55 

5g 

8 

3,500 

63.6 

33 

1.67 

106.2 

140.6 

.333 

21.22 
6.62 


17,400 

42 

3g 

6 

4,524 

107.7 

33 
1.274 
137.2 
176.0 

.425 

45.7 
3.85 


13,200 
31 

2g 

3 

3,320 

107.2 

47 

.66 

70.6 

140.5 

.3295 

35.3 
3.98 


30 


8 

2,250 

75 

10.8 

2.78 
208.2 


463 


34.7 


r  represents  rods;  g  represents  guns. 


COSTS 


Installation  costs  supplied  by  the  owners  ranged  between  $29.21 
and  $106.19  an  acre.  The  latter  figure  is  exceptionally  high  because 
the  cost  of  rebuilding  the  plant  after  its  destruction  by  fire  was  in- 
cluded. A  fair  average  seems  to  be  $37.50  an  acre,  as  represented  by 
"D"  in  table  6.  Operating  costs  for  a  single  application  varied  from 
$5.04  to  $12.69  an  acre,  or  .7  to  3.7  cents  per  gallon  of  spray.  This 
cost  depends  upon  the  kind  of  spray  used,  the  amount  per  tree,  the 
rate  of  application,  and  the  efficiency  of  the  plant.  These  figures 
include  all  labor,  material,  power  and  repairs. 


SUMMARY  AND   CONCLUSIONS 

A  stationary  spray  system  consists  of  a  central  pumping  station 
and  pipe  lines  laid  systematically  throughout  the  orchard,  with  outlets 
at  regular  intervals,  to  which  hose  are  attached  for  spraying  the  trees. 

The  first  stationary  spray  plant  was  used  by  Hayward  Reed,  in 
1908.      There  are  today  about  a  dozen  such  systems  in  California, 


Bul.  406] 


STATIONARY    SPRAY    PLANTS   IN    CALIFORNIA 


27 


TABLE  6 

Cost  of  Installation  and  Upkeep. 

Cost  of  Installation  (Owners'  figures) 


Test  group 


Total  first  cost 

Total  acres  piped 

Total    trees    under 

Pipe 

Installation  cost  per 

acre 

Installation  cost  per 

tree 


$15000.00 
260 

20,200 

$57.69 

$.743 


$10000.00 
250 

22,000 

$40.00 

$.454 


$6000.00 
563^ 

4300 

$106. 19 
$1,395 


$1875.00 
50 

5000 

$37.50 

$.375 


$1110.00 
38 

4350 

$29.21 

$.255 


$1560.00 
30 

2250 

$52.00 

$.693 


Note:    Group  "C"  is  high  due  to  irrigation  motor  cost  and  fire  repairs. 
Group  "D"  is  a  fair  example  of  what  cost  should  be. 

Operating  Costs  (Single  spraying) 


Test  group 


B 

c 

D 

E 

55 

42 

31 

3500 

4524 

3320 

42000 

17400 

13200 

$99.45 

$68.00 

$80.00 

<3 

$7.92* 

$12.80 

$2.64 

TJ 

$166.75 

$376.27 

$190.00 

£ 

$3.20 

$2.25 

$277.32 

$459.32 

$272.64 

$5,042 

$10,936 

$7,175 

$.079 

$.101 

$.063 

$.0066 

$.0264 

$.0208 

Acres  sprayed 

Trees  sprayed 

Gallons  of  spray 

Labor  cost 

Power  cost 

Material  cost 

Repairs 

Total  operating  cost 

Operating  cost  per  acre 

Operating  cost  per  tree 

Operating  cost  per  gallon. 


260 

20200 

89820 

$1661.81 

$23.00^ 

$1613.76 


$3298.57 
$12,687 
$.163 
$.0367 


Estimated. 


Fixed  Charges  (Based  on  s 

ystem  life 

of  15  years) 

Test  group 

A 

B 

C 

D 

E 

F 

Depreciation  per  year 

(6.66%) 

$1000.00 
900.00 

$666.67 
600.00 

$400.00 
360.00 

$125.00 
112.50 

$74.00 
66.60 

$104.00 

Interest  (6%) 

93.60 

Taxes 

Insurance 

Total 

$1900.00 
7.31 

1.46 
12.69 

$1266.67 
5.08 

1.01 
No  data 

$760.00 
13.46 

2.69 
5.04 

$237.50 
4.75 

0.95 
10.94 

$140.60 
3.70 

.74 

7.175 

$197.60 

Charge  per  acre 

6  58 

Charge  per  acre  single 
spraying  (based  on  5 
sprays  a  year) 

1.32 

Operating  cost  per  acre 
single  spraying 

No  data 

Total    cost   per    acre 
single  spraying 

$14.15 

$7.73 

$11.89 

$7,915 

28  UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 

the  orchards  ranging  in  size  from  19  to  260  acres,  while  in  the  state 
of  Washington  there  are  several  hundred  plants  in  orchards  from 
3  to  160  acres  in  size. 

The  advantages  of  stationary  spray  plants  are  many,  but  the 
principal  ones  are  that  spraying  may  be  done  on  time  in  spite  of 
adverse  soil  or  weather  conditions  and  that  pests  requiring  quick 
action  may  be  speedily  controlled.  Thorough  spraying  may  be  accom- 
plished with  a  saving  of  labor  and  time,  with  a  low  operating  cost  and 
low  fixed  charge.    Other  advantages  are : 

a.  It  is  possible  to  irrigate  and  spray  at  the  same  time. 

b.  Spraying  is  possible  with  a  minimum  danger  of  knocking  off 
or  bruising  the  fruit  on  low  hanging  branches. 

c.  Props  offer  little  interference  to  spraying. 

d.  Hillside  orchards  may  be  sprayed  easily. 

e.  Intercrops  or  permanent  cover  crops  are  not  injured,  since 

tractors  and  teams  are  not  required. 
/.  Men  are  separated  so  that  they  do  not  spray  each  other. 
g.  Electric  energy  may  be  used,  which  is  more  convenient  than 

gasoline  power. 
h.  Ninety-five  per  cent  of  the  time  is  used  in  spraying  and  no 

time  is  lost  in  refilling. 
i.  The  system  is  a  permanent  improvement  to  the  property. 

The  disadvantages  are : 

a.  Initial  cost  is  high.  This  is  not  a  great  disadvantage,  how- 
ever, considering  the  long  life  of  the  installation. 

b.  All  dependence  is  placed  in  one  plant. 

c.  The  system  is  limited  to  the  extent  of  the  pipe  lines. 

d.  There  is  some  possibility  of  materials  settling  in  the  pipes. 
With  mains  of  proper  size  and  with  sufficient  nozzles  in 
operation  to  maintain  velocity,  this  difficulty  becomes 
negligible. 

e.  There  is  a  possibility  of  damage  to  the  system  during  culti- 

vation, especially  when  subsoiling. 
/.  There  may  be  corrosion  of  the  pipes  and  fittings.     Proper 

flushing  after  each  spraying  minimizes  this  difficulty. 
g.  Some  spray  material  is  wasted  during  flushing. 
h.  There  is  loss  of  pressure  due  to  friction  in  long  pipes  and 

hose,  thus  necessitating  high  pump  pressures. 

There  is  a  possibility  of  combining  the  advantages  of  the  portable 
sprayer  and  the  stationary  spray  plant  by  piping  sections  of  the 
orchard  that  would  be  benefited  and  using  the  portable  sprayer  for 


BUL.  406]  STATIONARY    SPRAY   PLANTS   IN    CALIFORNIA  29 

supply  and  power.  In  other  words,  the  portable  rig  becomes  the 
pumping  station  for  the  permanent  piping  system  and  at  other  times 
is  available  for  spraying  parts  of  the  orchard  where  there  is  no  pipe 
line.  Some  growers  are  actually  using  this  combination  to  good 
advantage.  Other  growers  lay  the  piping  system  on  top  of  the 
ground,  but  this  method  is  suggested  only  as  a  temporary  measure. 

ACKNOWLEDGMENTS 

The  writers  desire  to  express  their  appreciation  to  Professor  L. 
J.  Fletcher,  who  was  largely  responsible  for  starting  this  investigation. 
Grateful  acknowledgment  is  due  to  Dr.  W.  L.  Howard  for  his  careful 
reading  and  revision  of  the  manuscript.  Thanks  are  also  due  to  Pro- 
fessor W.  P.  Tufts  and  Mr.  F.  A.  Hanson  for  their  suggestions  and 
assistance  during  this  investigation. 


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1925.     Some  facts  about  stationary  spray  plants.    Am.  Fruit  Growers  Maga- 
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STATION  PUBLICATIONS  AVAILABLE  FOR  FREE  DISTRIBUTION 


No. 

253.   Irrigation   and   Soil   Conditions  in  the 
Sierra  Nevada   Foothills,   California. 

261.  Melaxuma    of    the    Walnut,     "Juglans 

regia." 

262.  Citrus  Diseases  of   Florida   and   Cuba 

Compared  with  Those  of  California. 

263.  Size   Grades  for  Ripe  Olives. 

268.  Growing  and  Grafting  Olive  Seedlings. 
273.  Preliminary  Report  on  Kearney  Vine- 
yard  Experimental   Drain. 

275.  The     Cultivation     of     Belladonna     in 

California. 

276.  The  Pomegranate. 

277.  Sudan   Grass. 

278.  Grain    Sorghums. 

279.  Irrigation   of  Rice  in    California. 
283.  The  Olive  Insects  of  California. 
294.  Bean   Culture  in   California. 

304.  A  Study  of  the  Effects  of  Freezes  on 

Citrus    in    California. 
310.  Plum    Pollination. 

312.  Mariout  Barley. 

313.  Pruning      Young      Deciduous      Fruit 

Trees. 
319.  Caprifigs    and    Caprification. 

324.  Storage  of   Perishable  Fruit  at  Freez- 

ing Temperatures. 

325.  Rice     Irrigation     Measurements     and 

Experiments   in    Sacramento   Valley, 

1914-1919. 
328.   Prune   Growing   in    California. 
331.  Phylloxera-Resistant    Stocks. 
335.   Cocoanut   Meal   as   a   Feed   for   Dairy 

Cows   and    Other  Livestock. 

339.  The    Relative    Cost    of    Making    Logs 

from   Small  and  Large  Timber. 

340.  Control     of     the     Pocket     Gopher     in 

California. 

343.  Cheese    Pests    and    Their    Control. 

344.  Cold   Storage   as   an   Aid   to   the   Mar- 

keting of  Plums. 

346.  Almond    Pollination. 

347.  The  Control  of  Red  Spiders  in  Decid- 

uous Orchards. 

348.  Pruning  Young  Olive  Trees. 

349.  A    Study    of    Sidedraft    and    Tractor 

Hitches. 

350.  Agriculture      in      Cut-over      Redwood 

Lands. 

352.  Further  Experiments  in  Plum  Pollina- 

tion. 

353.  Bovine   Infectious   Abortion. 

354.  Results  of  Rice  Experiments  in   1922. 

357.  A     Self-mixing    Dusting    Machine    for 

Applying      Dry      Insecticides       and 
Fungicides. 

358.  Black    Measles,    Water    Berries,     and 

Related  Vine  Troubles. 

361.  Preliminary   Yield    Tables    for    Second 

Growth  Redwood. 

362.  Dust  and  the  Tractor  Engine. 

363.  The  Pruning  of  Citrus  Trees  in  Cali- 

fornia. 

364.  Fungicidal   Dusts    for   the    Control    of 

Bunt. 

365.  Avocado  Culture  in  California. 


BULLETINS 
No. 
366. 


367. 

368. 

369. 

370. 
371. 

372. 

373. 

374. 

375. 

376. 

377. 
379. 
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382. 

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385. 
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390. 

391. 

392. 
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394. 

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398. 
399. 


400. 
401. 

402. 
403. 
404. 
405. 
406. 


Turkish  Tobacco  Culture,  Curing  and 
Marketing. 

Methods  of  Harvesting  and  Irrigation 
in  Relation  of  Mouldy  Walnuts. 

Bacterial  Decomposition  of  Olives  dur- 
ing Pickling. 

Comparison  of  Woods  for  Butter 
Boxes. 

Browning  of  Yellow  Newtown  Apples. 

The  Relative  Cost  of  Yarding  Small 
and   Large  Timber. 

The  Cost  of  Producing  Market  Milk  and 
Butterfat  on  246  California  Dairies. 

Pear   Pollination. 

A  Survey  of  Orchard  Practices  in  the 
Citrus  Industry  of  Southern  Cali- 
fornia. 

Results  of  Rice  Experiments  at  Cor- 
tena,    1923. 

Sun-Drying  and  Dehydration  of  Wal- 
nuts. 

The  Cold   Storage  of  Pears. 

Walnut   Culture   in   California. 

Growth  of  Eucalyptus  in  California 
Plantations. 

Growing  and  Handling  Asparagus 
Crowns. 

Pumping  for  Drainage  in  the  San 
Joaquin    Valley,    California. 

Monilia  Blossom  Blight  (Brown  Rot) 
of  Apricot. 

Pollination    of    the    Sweet    Cherry. 

Pruning  Bearing  Deciduous  Fruit 
Trees. 

Fig  Smut. 

The  Principles  and  Practice  of  Sun- 
drying  Fruit. 

Berseem  or  Egyptian   Clover. 

Harvesting  and  Packing  Grapes  in 
California. 

Machines  for  Coating  Seed  Wheat  with 
Copper    Carbonate   Dust. 

Fruit    Juice    Concentrates. 

Crop  Sequences  at  Davis. 

Cereal  Hay  Production  in  California. 
Feeding  Trials  with  Cereal  Hay. 

Bark  Diseases  of  Citrus  Trees. 

The  Mat  Bean  (Phaseolus  aconilifo- 
lius). 

Manufacture  of  Roquefort  Type  Cheese 
from    Goat's   Milk. 

Orchard  Heating  in  California. 

The  Blackberry  Mite,  the  Cause  of 
Redberry  Disease  of  the  Himalaya 
Blackberry,    and   its   Control. 

The  Utilization  of  Surplus  Plums. 

Cost    of    Work    Horses    on    California 

The  Codling  Moth  in  Walnuts. 

Farm-Accounting  Associations. 

The  Dehydration  of  Prunes. 

Citrus  Culture  in  Central  California. 

Stationary  Spray  Plants  in  California. 


CIRCULARS 


No. 

87.  Alfalfa. 
117.  The    Selection    and    Cost    of    a    Small 

Pumping  Plant. 
127.  House   Fumigation. 
129.  The  Control  of  Citrus  Insects. 
136.  Melilotus    indica    as    a    Green-Manure 

Crop  for  California. 
144.  Oidium    or    Powdery    Mildew    of    the 

Vine. 


No. 

157.  Control  of  the  Pear  Scab. 

160.  Lettuce  Growing  in  California. 

164.    Small  Fruit  Culture  in   California. 

166.   The   County  Farm  Bureau. 

170.  Fertilizing     California     Soils    for    the 

1918   Crop. 
173.  The    Construction    of   the   Wood-Hoop 

Silo. 
178.  The  Packing  of  Apples  in   California. 


CIRCULARS—  (Continued) 


No.  No. 

179.  Factors    of    Importance   in    Producing  265. 

Milk  of  Low  Bacterial   Count.  266. 

190.  Agriculture  Clubs  in  California. 
199.   Onion    Growing  in    California.  267. 

202.  County   Organizations   for   Rural   Fire 

Control.  269. 

203.  Peat   as   a  Manure   Substitute.  270. 

209.  The  Function  of  the  FaTm  Bureau.  272. 

210.  Suggestions  to  the  Settler  in  California. 

212.   Salvaging    Rain-Damaged    Prunes.  273. 

215.   Feeding  Dairy  Cows  in  California.  274. 

217.  Methods   for   Marketing  Vegetables   in 

California.  276. 

220.   Unfermented   Fruit  Juices.  277. 

228.  Vineyard  Irrigation  in  Arid  Climates. 

230.  Testing  Milk,    Cream,    and   Skim  Milk  278. 

for  Butterfat. 

231.  The    Home    Vineyard.  279. 

232.  Harvesting    and    Handling    California 

Cherries    for    Eastern    Shipment.  281. 

234.  Winter  Injury  to  Young  Walnut  Trees 

during  1921-22. 

235.  Soil     Analysis     and     Soil     and     Plant  282. 

Inter-relations. 

236.  The     Common    Hawks     and     Owls    of  283. 

California    from    the    Standpoint    of  284. 

the  Rancher.  285. 

237.  Directions  for  the  Tanning  and  Dress-  286. 

ing  of  Furs.  287. 

238.  The  Apricot  in  California.  288. 

239.  Harvesting     and     Handling     Apricots  289. 

and  Plums  for  Eastern  Shipment.  290. 

240.  Harvesting    and    Handling    Pears    for  291. 

Eastern  Shipment. 

241.  Harvesting  and  Handling  Peaches  for  292. 

Eastern   Shipment.  293. 

243.  Marmalade  Juice  and  Jelly  Juice  from  294. 

Citrus  Fruits.  295. 

244.  Central  Wire  Bracing  for  Fruit  Trees. 

245.  Vine   Pruning   Systems.  296. 

247.  Colonization    and    Rural   Development. 

248.  Some    Common    Errors    in    Vine  Prun-  298. 

ing  and  Their  Remedies. 

249.  Replacing    Missing    Vines.  299. 

250.  Measurement   of    Irrigation   Water   on  300. 

the  Farm.  301, 

252.  Supports  for  Vines.  302. 

253.  Vineyard  Plans.  303. 

254.  The  Use  of  Artificial  Light  to  Increase 

Winter   Egg    Production.  304, 

255.  Leguminous  Plants  as  Organic  Fertil-  305, 

izer    in    California    Agriculture.  306. 

256.  The   Control   of  Wild   Morning   Glory. 

257.  The  Small-Seeded  Horse  Bean.  307. 

258.  Thinning   Deciduous   Fruits. 

259.  Pear  By-products. 

261.  Sewing  Grain  Sacks. 

262.  Cabbage  Growing  in   California. 

263.  Tomato  Production  in  California. 

264.  Preliminary      Essentials      to      Bovine 

Tuberculosis  Control. 


Plant  Disease  and  Pest  Control. 

Analyzing  the  Citrus  Orchard  by 
Means   of    Simple   Tree   Records. 

The  Tendency  of  Tractors  to  Rise  in 
Front;    Causes   and   Remedies. 

An  Orchard  Brush  Burner. 

A  Farm  Septic  Tank. 

California  Farm  Tenancy  and  Methods 
of  Leasing. 

Saving  the  Gophered  Citrus  Tree. 

Fusarium  Wilt  of  Tomato  and  its  Con- 
trol by  Means  of  Resistant  Varieties. 

Home  Canning. 

Head,  Cane,  and  Cordon  Pruning  of 
Vines. 

Olive  Pickling  in  Mediterranean  Coun- 
tries. 

The  Preparation  and  Refining  of  Olive 
Oil  in    Southern   Europe. 

The  Results  of  a  Survey  to  Determine 
the  Cost  of  Producing  Beef  in  Cali- 
fornia. 

Prevention  of  Insect  Attack  on  Stored 
Grain. 

Fertilizing  Citrus  Trees  in  California. 

The  Almond  in   California. 

Sweet  Potato  Production  in  California. 

Milk  Houses  for  California  Dairies. 

Potato   Production   in   California. 

Phylloxera  Resistant  Vineyards. 

Oak  Fungus  in  Orchard  Trees. 

The  Tangier  Pea. 

Blackhead  and  Other  Causes  of  Loss 
of  Turkeys  in  California. 

Alkali  Soils. 

The    Basis   of   Grape    Standardization. 

Propagation   of   Deciduous   Fruits. 

The  Growing  and  Handling  of  Head 
Lettuce  in   California. 

Control  of  the  California  Ground 
Squirrel. 

The  Possibilities  and  Limitations  of 
Cooperative  Marketing. 

Poultry   Breeding  Records. 

Coccidiosis  of  Chickens. 

Buckeye  Poisoning  of  the  Honey  Bee. 

The   Sugar  Beet  in   California. 

A  Promising  Remedy  for  Black  Measles 
of  the  Vine. 

Drainage  on  the  Farm. 

Liming  the  Soil. 

A  General  Purpose  Soil  Auger  and  its 
Use  on  the  Farm. 

American   Foulbrood   and  its    Control. 


The  publications  listed  above  may  be  had  by  addressing 

College  of  Agriculture, 

University  of  California, 

Berkeley,  California. 


10m-10,'26 


